1. Field of the Invention
The present invention relates to a manufacturing method of a liquid discharge head for discharging liquid, and specifically relates to a manufacturing method of an ink jet recording head which performs recording by discharging ink on a recording medium.
2. Description of the Related Art
As an example of use of the liquid discharge head for discharging liquid, there is an ink jet recording head applied to an ink jet recording method for performing recording by discharging ink on a recording medium.
U.S. Pat. No. 6,471,901 discusses an ink jet recording head as described below. A substrate on which energy generating elements for generating energy used to discharge liquid such as ink are provided and a discharge element substrate which is provided on the substrate and includes liquid discharge ports and a flow path wall member in which a flow path is provided. The substrate with energy generating elements and the discharge element substrate are electrically connected to a flexible wiring substrate. The side surfaces of the substrate are coated with an end surface sealing member for protecting the side surfaces from ink, dust, and the like.
However, when a difference of a linear expansion coefficient between two members is very large such as in a case of a silicon substrate and a flow path wall member made of a resin, a joint strength between the substrate and the flow path wall member may be not sufficient, and there is a risk that peeling occurs. When the peeling occurs, there may be problems as described below. For example, when providing an end surface sealing member for covering the entire side surfaces of the substrate to reliably protect side surfaces of the substrate, the sealing material may reach the top surface of the substrate depending on viscosity and fluidity of the sealing material for forming the sealing member. In this case, the sealing material may reach the side surface of the flow path wall member, and intrude into a gap between the flow path wall member and the substrate depending on the physical property of the sealing material. Due to the intrusion of the sealing material, the joint strength of the joint section between the substrate and the flow path wall member decreases, so that there is a risk of peeling. In addition, there may be a risk that liquid such as ink intrudes into the same gap. In particular, when an ink jet recording head is elongated, or the flow path wall member is thickened, the above risks increase because the stress of the flow path wall member increases.